US doctors warn of small but alarming rates of a flesh-eating type of superbug.

Patients appear to have caught the MRSA infection that attacks the skin outside of hospital, reports the New England Journal of Medicine.

At a centre in California, 14 patients were identified between 2003 and 2004, and some needed to be hospitalised.

So far no cases have been seen in the UK, but health officials said they were monitoring the situation.

We have recently noted an alarming number of these infections

The study authors

The infections in the US community have typically manifested as skin infections, such as pimples and boils, in otherwise healthy people.

Although none of the 14 patients died, they had serious complications, including the need for reconstructive surgery and prolonged stay in the intensive care unit.

The disease is different to MRSA infections seen in the UK, which occur most frequently among people in hospitals who have weakened immune systems.

The CDC has been investigating clusters of the community-acquired MRSA skin infections among athletes, military recruits and prisoners.

Spreading

A common theme associated with the spread of these MRSA skin infections appears to be close skin-to-skin contact, openings in the skin such as cuts or abrasions, contaminated items and surfaces, crowded living conditions and poor hygiene.

The CDC is investigating why this strain is particularly good at spreading.

The study authors, from the University of California, Los Angeles, said: "We have recently noted an alarming number of these infections caused by community-associated methicillin-resistant Staphylococcus aureus (MRSA)."

They recommended that in areas in which the infection is endemic, suspected cases should be promptly treated with antibiotics.

In the UK, there have been some cases of MRSA in the community, but experts say these are different to the cases arising in the US.

Angela Kearns, head of the Health Protection Agency's staphylococcus reference laboratory, said: "Over the past three years the Agency has seen only a small number of community-acquired MRSA cases, and the UK hasn't seen the levels of true community MRSA that have been seen in the States.

"Consequently, the risk of contracting this type of MRSA in the UK remains extremely small."

Dr Jodi Lindsay, lecturer in infectious diseases at St George's hospital, said although no cases had been reported in the UK yet, it was a concern.

"We are worried these community-acquired MRSAs might come over here from the US," she said.